They are called millimeter lines.
you read a ruler by conting the little lines first
you draw straight lines with a ruler
Try using what they call a Horizontal Ruler: <hr> You can also indicate the width, <hr width="50%">
A 16-mark looks like a small vertical line that is slightly longer than the surrounding lines on a standard ruler. It typically falls between the 15-mark and the 17-mark on the ruler scale.
DOODOO
If the lines are on the opposite side of the inches on the ruler, then yes. You must keep in mind, however, that a ruler is used for inches and that the centimeters may not be marked.
Because he rules People "rule" lines - Wikipedia
The millimeters on a ruler are the tiny lines in between each centimeter
An Ancient Ruler.
Ruler
it means halfs